Liberon spirit wood dye and french polish?

[rob.]

So I bought some wood dye, I was planning to French polish ontop of it, the back of the bottle says not compatible with French polish or shellac base sealers.
Why is that guys? What would happen if I used it? Would the methylated spirits dissolve the dye?

 

[marcros]

the same solvent is being used for both the dye and the polish. so as you apply the french polish the dye will lift

 

[rob.]

That's what I'm thinking, however it says here it can be polished over with French polish.

http://www.woodcareexpert.co.uk/liberon ... t-wood-dye

I guess I'll have to try a test piece and see how it goes.

 

[oakmitre]

Stained wood with clear lacquer on top VS coloured lacquer.

If the stain is soluble (or mobile during application) in the solvent of the next layer that is what you are looking at.

I know because I have done it and failed

 

[marcros]

you could give Liberon's technical dept a call- they are usually pretty good. It doesnt make sense to me that you can use french polish over it.

 

[rob.]

So the dye will or could effectively put colour into the French polish?
The dye will be used on small parts of the job to blend new wood in with old, it will be put on in layers with an artists brush to build up to the right colour, perhaps when allowed to fully dry a coat of French polish could be applied using the same method and allowed to cure before the final polish using a fad?

 

[rob.]

you could give Liberon's technical dept a call- they are usually pretty good. It doesnt make sense to me that you can use french polish over it.

That's probably the way to go, it makes no sense to me either.

 

[woodbrains]

Hello,

Liberon make ethanol based, water based and spirit based dyes. Seems like you have the ethanol based one.

Usually you would use the one that was dissimilar to the polish's solvent. So the spirit based one recommends caution when applying an oil finish; this would be good however, for shellac/French polish.

If you've not opened the dye, perhaps you could exchange it.

Mike.

 

[oakmitre]

I am not a French polisher - but if you were going to make a paint yourself or coloured varnish - you would add pigment to a solvent and binder.

If the stain below mixes into the above layer of shellac and alcohol as you apply it, you are effectively mixing your own brand of paint in an uncontrolled manner.

The effect you will get will vary from being okay to flat coloured, to glossy paint. It really depends if the original stain is dye based ( transparent ) or pigment based ( opaque ). Also how concentrated and mobile the colourant is.

 

[woodbrains]

I am not a French polisher - but if you were going to make a paint yourself or coloured varnish - you would add pigment to a solvent and binder.

If the stain below mixes into the above layer of shellac and alcohol as you apply it, you are effectively mixing your own brand of paint in an uncontrolled manner.

The effect you will get will vary from being okay to flat coloured, to glossy paint. It really depends if the original stain is dye based ( transparent ) or pigment based ( opaque ). Also how concentrated and mobile the colourant is.

Hello,

Dye should not contain pigment, in which case you will not get paint!

However, a lot of these dyes, are actually dye / stains, which contain both dye and pigment. I don't know if Liberon is like this, though.

It is not 'making paint' that is the issue, but the removal of the dye when applying the polish, which leads to patchy results.

Mike.

 

[oakmitre]

Even if the pigment or stain was present in vast amounts such that is would not be removed by the solvent to produce the patchy effect on the wood surface, it would still change the appearance.

This is because in the perfect scenario, the upper layer of lacquer or varnish is as clear as possible. Once the slightest murky element is introduced to the lacquer it will look different in the way it reflects light.

I know this after using Indian Ink to stain wood. Carbon black is very potent, and even if some of it lifts its wood staining power can still remain. The particles flowed into the clear varnish above and produced a range of effects depending on the solvent type and film thickness of clear finish, from matt to gloss to blotchy something looking like japaned black.

I would alway class pigment as insoluble (but possibly mobile) and dye as soluble.

 

[rob.]

This is going on cock beading on a Georgian antique chest, after applying the French polish the sheen will be cut back with fine wire wool and wax, so it might not cause a huge problem, I'll try a test piece and see how it goes. The repair wont be invisible anyway but I don't want it to hurt to look at it either.

 

[ED65]

You might try sealing with a little thinned varnish. This will slow down the job quite a bit but it should allow you to use the shellac over the alcohol-based dye without lifting problems.